Broadband probes for impedance tuners

1. A probe for a slab line impedance tuner system operable over a frequency bandwidth, the tuner system including opposed slab conductor plates and a center conductor disposed between the slab conductor plates, a probe carriage and a drive system for moving the probe carriage in a longitudinal direction parallel to the center conductor, the probe comprising:

a plurality of probe sections mounted adjacent to one another with no gaps between adjacent probe sections, wherein each probe section has a different characteristic impedance from every other probe section at some position in the range of the longitudinal directional movement of the probe; and

wherein a number of the probe sections forming the plurality of probe sections is sufficient to provide a desired characteristic impedance transformation for the frequency bandwidth, wherein the characteristic impedance of the tuner system is transformed probe-section by probe-section by the probe to intermediate impedance values to reach a target impedance value.

2. The probe of claim 1 , wherein the plurality of probe sections are separate pieces supported for movement together along the center conductor and in a direction transverse to the center conductor.

3. The probe of claim 1 , wherein the plurality of probe sections are fabricated together as a unitary one-piece structure.

4. The probe of claim 1 , wherein each of the plurality of probe sections is at a different height relative to the center conductor to achieve the said different characteristic impedance of each probe from every other probe section.

5. The probe of claim 1 , wherein each probe section has a cross-sectional profile defining a trough configured to straddle the center conductor, and wherein the cross-sectional profile of each of respective ones of the plurality of probe sections is such that the troughs are wider for each successive probe section along the longitudinal direction to achieve the said different characteristic impedance of each probe from every other probe section.

6. The probe of claim 1 , wherein each probe section has a cross-sectional profile defining a trough configured to straddle the center conductor, and wherein each of the plurality of probe sections is at a different height relative to the center conductor and wherein the cross-sectional profile of each of the plurality of probe sections is such that the troughs are wider for each successive probe along the longitudinal direction to achieve the said different characteristic impedance of each probe from every other probe section.

7. The probe of claim 1 , wherein each probe section has a nominal length dimension along the longitudinal direction of one quarter wavelength at a frequency at a midpoint of the bandwidth.

8. A slab line impedance tuner system operable over a frequency bandwidth, the tuner system comprising:

a slab line transmission including opposed slab conductor planes and a center conductor disposed between the slab conductor planes;

a probe;

a probe carriage carrying the probe;

a carriage drive system for moving the probe carriage in a longitudinal direction parallel to the center conductor;

a probe drive system for moving the probe in a transverse direction relative to the center conductor to position the probe closer to or further away from the center conductor; and

wherein the probe includes:

a plurality of probe sections mounted adjacent to one another with no gaps between adjacent sections, wherein each probe section has a different characteristic impedance from every other probe section at some position in the range of the longitudinal directional movement of the probe; and

wherein a number of the probe sections forming the plurality of probe sections is sufficient to provide a desired characteristic impedance transformation for the frequency bandwidth, wherein the characteristic impedance of the tuner system is transformed probe-section by probe-section by the probe to intermediate impedance values to reach a target impedance value.

9. The system of claim 8 , wherein the plurality of probe sections are separate pieces supported for movement together along the center conductor and in a direction transverse to the center conductor.

10. The system of claim 8 , wherein the plurality of probe sections are fabricated together as a unitary one-piece structure.

11. The system of claim 8 , wherein each of the plurality of probe sections is at a different height relative to the center conductor to achieve the said different characteristic impedance of each probe from every other probe section.

12. The system of claim 8 , wherein each probe section has a cross-sectional profile defining a trough configured to straddle the center conductor, and wherein the cross-sectional profile of each of respective ones of the plurality of probe sections is such that the troughs are wider for each successive probe section along the longitudinal direction to achieve the said different characteristic impedance of each probe from every other probe section.

13. The system of claim 8 , wherein each probe section has a cross-sectional profile defining a trough configured to straddle the center conductor, and wherein each of the plurality of probe sections is at a different height relative to the center conductor and wherein the cross-sectional profile of each of the plurality of probe sections is such that the troughs are wider for each successive probe along the longitudinal direction to achieve the said different characteristic impedance of each probe from every other probe section.

14. The system of claim 8 , wherein each probe section has a nominal length dimension along the longitudinal direction of one quarter wavelength at a frequency at a midpoint of the bandwidth.

15. A probe for a slab line impedance tuner system operable over a frequency bandwidth, the tuner system including opposed slab conductor planes and a center conductor disposed between the slab conductor planes, a probe carriage and a drive system for moving the probe carriage in a longitudinal direction parallel to the center conductor, the probe comprising:

a plurality of quarter wavelength, electrically conductive probe sections, each probe section having a nominal length dimension along the longitudinal direction of one quarter wavelength at a frequency at a midpoint of the bandwidth, and wherein each probe section has a cross-sectional profile defining a trough configured to straddle the center conductor as the probe is moved transversely toward the center conductor;

wherein the probe sections are supported for movement together along the center conductor and in a direction transverse to the center conductor, the probe sections mounted together with no gaps between adjacent probe sections; and

wherein a number of the probe sections forming the plurality of probe sections is sufficient to provide a desired characteristic impedance transformation for the frequency bandwidth, wherein the characteristic impedance of the tuner system is transformed probe-section-by-probe-section by the probe to intermediate impedance values to reach a target impedance value.

16. The probe of claim 15 , wherein the probe sections are positioned next to each other and at stepped heights of the trough relative to the center conductor of the slab line.

17. The probe of claim 15 , wherein the probe sections are positioned next to each other and at the same height relative to the center conductor of the slab line, and wherein the cross-sectional profile of each of the plurality of probe sections is varied such that the troughs are wider for each successive probe section.

18. The probe of claim 15 , wherein the probe sections are positioned next to each other and at stepped heights relative to the center conductor of the slab line, and wherein the cross-sectional profile of each of the plurality of probe sections is varied such that the troughs are wider for each successive probe section.